1. Field of the Invention
The present invention relates to a system and method of pointed position detection, a presentation system, and also a program.
2. Description of Related Art
In a presentation system that makes use of a projector or the like, it is necessary to detect the position of a pointer implemented by a pointer implement. In such a case, it is important to accurately detect the pointed position without having to use a special pointer implement or the like.
Various techniques are being investigated, such as one in which auxiliary illumination such as infrared light is used, the shadow of a pointer implement that is cast by this infrared light is imaged by a CCD camera or the like, and detection of the position of this pointer is based on an imaging signal therefrom. A particular problem in such a case concerns the low detection sensitivity with respect to an image formed by infrared light that is taken by the CCD camera. A CCD camera has a narrower dynamic range for infrared light than for usual visible light. It is therefore unable to pick up an infrared image efficiently. This is considered to be one cause leading to the reduction in position detection accuracy.
The present invention was devised in the light of the above described technical problem and has as an objective thereof the provision of a system and method of pointed position detection, a presentation system, and also a program for accurate pointed position detection based on an infrared image or the like.
(1) In order to solve the above described technical problem, a pointed position detection system in accordance with the present invention comprises:
image pick-up means which picks up an image of an image display region; and
position detection means which detects a position that is pointed by a pointing image within the image display region, based on image information obtained by the image pick-up means;
wherein the position detection means comprises:
movement detection means which detects movement of the pointing image; and
pointed position detection means which detects the pointed position of the pointing image when movement of the pointing image has halted.
(2) According to the present invention, there is provided a pointed position detection system comprising:
image pick-up section which picks up an image of an image display region; and
position detection section which detects a position that is pointed by a pointing image within the image display region, based on image information obtained by the image pick-up section;
wherein the position detection section comprises:
movement detection section which detects movement of the pointing image; and
pointed position detection section which detects the pointed position of the pointing image when movement of the pointing image has halted.
(3) A presentation system in accordance with the present invention comprises display means which display an image in the image display region, and the above-described pointed position detection system to detect the pointed position of the pointing image.
(4) According to the present invention, there is provided a computer-usable program for implementing a presentation system, the program that is embodied on an information storage medium or in a carrier wave, further implementing on a computer:
means for causing image pick-up means to pick up an image of an image display region; and
position detection means which detects a position that is pointed by a pointing image within the image display region, based on image information obtained by the image pick-up means;
wherein the position detection means comprises:
movement detection means which detects movement of the pointing image; and
pointed position detection means which detects the pointed position of the pointing image when movement of the pointing image has halted.
(5) A pointed position detection method in accordance with the present invention comprises:
an image picking-up step of picking up an image of an image display region; and
a position detection step of detecting a position that is pointed by a pointing image within the image display region, based on image information obtained in the image picking-up step;
wherein the position detection step comprises:
a step of detecting movement of the pointing image; and
a step of detecting the pointed position of the pointing image when movement of the pointing image has halted.
This aspect of the present invention makes it possible to perform accurate position detection by boosting the S/N ratio of the captured image, even if it is assumed that the image pick-up means has a bad S/N ratio, by using a configuration by which movement of the pointing image is detected and a still image of the pointing image is captured after confirmation that the movement has halted, then pointed position detection is based on the captured still image.
(6) In each of the above pointed position detection system, presentation system, and program, the image pick-up means may pick up an infrared image of the image display region which is formed by infrared light;
the movement detection means may detect movement of the pointing image based on the infrared image formed by infrared light; and
the pointed position detection means may detect the pointed position of the pointing image based on the infrared image formed by infrared light.
This makes it possible to separate the projected background image and the pointing image efficiently, thus enabling efficient movement detection with a simple configuration, when the light for an image is projected from the projector onto the image display region, by way of example.
It also makes it possible to perform position detection based on an infrared image without using any special means, thus simplifying the system configuration.
Note that infrared light generally ranges in wave-length from 700 nm to 1 mm.
(7) In each of the pointed position detection system, presentation system, and program,
the image pick-up means may pick up an infrared image of the image display region formed by infrared light and a visible-light image of the image display region formed by visible light;
the movement detection means may detect movement of the pointing image based on the infrared image formed by infrared light; and
the pointed position detection means may detect the pointed position of the pointing image based on the visible-light image formed by visible light.
This makes it possible to separate the projected background image and the pointing image efficiently, thus enabling efficient movement detection with a simple configuration.
In such a case, it is preferable to provide switching between a filter for visible light and a filter for infrared light, in the light path in front of the image pick-up means.
More specifically, a shutter configuration could be enabled or infrared and visible-light filters could be provided to cover the two halves of a circular filter mechanism, where the mechanism is switched by a motor drive.
If the image pick-up means is implemented by a CCD camera, by way of example, this aspect of the invention makes it possible to provide imaging by a single CCD camera, instead of a plurality of CCD cameras for taking images formed by visible light and infrared light.
This capturing of a still image as an image formed by visible light during position detection enables an increase in the dynamic range of the thus-captured image, thus making it possible to achieve accurate position detection that is not affected by ambient noise around the pointing image.
Note that the visible light generally ranges in wavelength from 400 nm to 700 nm.
(8) In each of the above pointed position detection system, presentation system, and program,
the image pick-up means may pick up an infrared image of the image display region formed by infrared light and a visible-light image of the image display region formed by visible light;
the movement detection means may detect movement of the pointing image based on the visible-light image formed by visible light; and
the pointed position detection means may detect the pointed position of the pointing image based on the infrared image formed by infrared light.
In such a case, the above described method ensures a reduction in ambient noise and accurate position detection, by enabling imaging while the light is switched between visible light and infrared light, and also by taking an infrared image as a still image.
(9) In each of the above pointed position detection system and presentation system, the image pick-up means may pick up an image formed by infrared light, through an infrared transmission section that allows only infrared light to pass.
This ensures accurate position detection by removing unnecessary light components to reduce noise, by taking an infrared image through the infrared transmission section.
(10) Each of the pointed position detection system and presentation system may further comprise an auxiliary light source which projects infrared light towards the image display region when picking up an image formed by infrared light.
This provision of an auxiliary light source ensures that an infrared image is picked up even in locations where there is no sunlight.
(11) In each of the pointed position detection system and presentation system, the image pick-up means may includes adjusting means which adjusts exposure time such that an image is taken with a predetermined short exposure time during the detection of movement of the pointing image, but an image is taken with a long exposure time that is longer than the short exposure time during the detection of the pointed position of the pointing image.
(12) The program may further comprise information for implementing adjusting means which adjusts exposure time such that an image is taken with a predetermined short exposure time during the detection of movement of the pointing image, but an image is taken with a long exposure time that is longer than the short exposure time during the detection of the pointed position of the pointing image.
This makes it possible to obtain an image with a high S/N ratio, which is necessary for position detection, by lengthening the exposure time, thus ensuring accurate position detection. When position detection is done by using infrared light, the sensitivity of a CCD camera for infrared light is less than that for visible light, so that use of this method ensures a sufficiently large dynamic range even when infrared light is used for position detection, ensuring accurate position detection.
(13) The pointed position detection system may further comprise projection means which projects light for forming a uniform image towards the image display region during the detection of the pointed position of the pointing image.
(14) In the above presentation system, the display means may displays a uniform image during the detection of the pointed position of the pointing image.
(15) The program may further implement on a computer, projection means which projects light for forming a uniform image towards the image display region during the detection of the pointed position of the pointing image.
This ensures that no background intrudes into the thus-captured image and also that only the pointing image is captured, thus making it possible to detect the pointed position thereof accurately.
Note that, in this case, a uniform image is preferably a flash image that is displayed for an instant.
(16) Each of the pointed position detection system and presentation system may further comprise processing means which performs predetermined determination processing when a halt of movement of the pointing image is detected for at least a predetermined time, based on a detection result of the pointed position detection means.
(17) The program may further implement on a computer, processing means which performs predetermined determination processing when a halt of movement of the pointing image is detected for at least a predetermined time, based on a detection result of the pointed position detection means.
This enables determination of the pointed position.
In this case, means for executing a predetermined program when a halt of movement of the pointing image is detected for at least a predetermined time could be applied as the processing means which performs the predetermined determination processing.
(18) In each of the pointed position detection system, presentation system, and program, the processing means which performs predetermined determination processing may comprise:
changing means which changes a display of the pointing region when a pointer implement is halted for less than the predetermined time; and
processing means which performs the determination processing when the halting of the pointer implement continues after the display change of the pointing region.
This makes it possible that selection of an icon displayed in the image display region can be visually conveyed to the presenter by changing the display state of the icon after clicking of the icon, by way of example, thus making it possible to prevent erroneous operation and give the presenter a more enhanced operating experience.